What a fascinating subject matter. You mention this in your preface, but would you mind again going through what the process was that got you interested in chemical weapons in the Civil War and led to the writing of this book? It started with you accidentally discovering a letter while you were doing research for another topic, if I’m correct.

That’s right. My historical research has focused on Civil War medicine, and my reading has included literature on the roles that Civil War scientists and health practitioners played outside medical care. Some of those sources mentioned ideas for chemical weapons, but the same ideas were covered repeatedly, so I assumed that the subject was exhausted and didn’t warrant further research. Then I stumbled on a letter in which a Confederate surgeon proposed chemical weapons that had not appeared in anything I had read before. That accident suggested that there might be additional proposals waiting to be discovered, and I ended up finding a lot of ideas that had not been previously described. Civil War weaponry is not my field, but chemical agents clearly fall within my medical interest. After all, medical personnel would have been responsible for treating victims of chemical weapons. As it turns out, most of the chemicals proposed as weapons had medicinal uses, and many of the weapons’ proponents were physicians.

Gabriel James Rains, a Confederate general, described one device he designed as “a most infernal contrivance to do evil.” What sort of ethical concerns did political and military leaders have about using chemical weapons? Were they dismayed, or were they willing to embrace the view in William Tecumseh Sherman’s famous quote that “war is cruelty, and you cannot refine it”?

I think the answer depends on the intent of the weapon. Many of the weapons were supposed to temporarily subdue the enemy without causing lasting harm, and ethical objections to these were minimal. There was a general aversion to weapons that maimed or killed in an underhanded or dishonorable manner, such as land mines and poisons. Since most politicians and military men claimed to put great value on honor, they would generally have objected to the lethal poisons, at least in public pronouncements. Weapons that were unnecessarily cruel were also condemned. On the other hand, the proponents of the weapons said that desperate times demanded desperate measures, even if those measures seemed morally questionable. Some individuals pointed out that it was more merciful to kill enemy soldiers quickly and painlessly with poison than to mangle them with projectiles and leave them to die agonizingly on the battlefield. Sherman’s quotation might suggest that he would accept the necessity of chemical weapons, but professional soldiers could have seemingly inconsistent views. Civil war troops used conventional weapons to inflict horrible suffering on the enemy, yet one leader of such troops, George McClellan, objected to an incendiary weapon as being outside the bounds of “civilized warfare.” I guess that term, to some people, was not an oxymoron.

You say that a lot of inventors were foiled by the government not taking their ideas seriously, even if some of the proposed devices were quite practical. What do you think was behind the reluctance by both the United States and the Confederate governments to consider and implement these sorts of weapons?

It’s well documented that the chief of the U.S. ordnance department was less than open to the ideas, and the same was probably true on the Confederate side, although there’s less direct evidence for that. Both sides had their hands full trying to supply their troops with conventional weapons and would be understandably reluctant to spend time studying unproven concepts. Besides, to a trained military man, it was clear at a glance that most of the suggestions would not work as intended on the battlefield. It must have been maddening for weapons experts to receive unwelcome advice about their own specialty, especially from civilians.

A good percentage of those proposing chemical weapons were physicians. Most of the chemicals suggested for military use had medicinal purposes as well, so physicians would be familiar with them, and yet proposals for chemical weapons seem to fly utterly in the face of our ideas of doctors and a “do no harm” philosophy. Did it surprise you that many of the civilians on both sides proposing chemical weapons were physicians or had some sort of medical background?

Yes, that was a big surprise. I think part of the reason is that our modern concept of a physician differs from the reality of the Civil War era. In those days, there was essentially no regulation of medical practice, so you could call yourself a physician without graduating from a medical school or passing a licensing exam. To get a medical degree, you attended two usually identical sets of lectures, each of which took only several months, and completed an apprenticeship and thesis. The major barrier to entering a medical school was paying for the lectures. Clearly, becoming a physician back then didn’t entail the tremendous expense and devotion as it does today, and it was common for people who practiced medicine or had a medical degree to have other occupations. It’s my guess that the ethical standards and commitment to the profession that we associate with today’s physicians were not embraced as strongly by many physicians of the Civil War era. It’s notable that many physicians joined the Union or Confederate ranks hoping to experience combat, so my findings are not an isolated example of medical men acting contrary to the “do no harm” principle.

There are some proposals in the book that seem quite silly on the surface, such as throwing cayenne pepper onto a ship to irritate the soldiers fighting there. Yet you point out that in a lot of ways, ideas like this are very similar to modern-day pepper spray. Even concepts that might seem almost laughable to us like stink pots have modern-day counterparts in substances used by Israeli police. Were you ever surprised while researching at how some of the proposed (and even ridiculed) devices foreshadowed modern concepts and technology?

Yes. The one that surprised me the most was a proposal to place two relatively safe chemicals in an artillery shell and have them mix during flight to form deadly hydrogen cyanide, which would be released when the shell exploded. This was a so-called binary weapon, and the same concept appeared during the Cold War, for example, in an American artillery projectile designed to deliver the nerve agent sarin. Not only that, the chemicals suggested during the Civil War were used in American gas chambers starting in the 1930s and decades later in terrorist bombs. In this instance, the proponent got the general idea and the specific ingredients right, although it’s unclear whether the delivery system he suggested would have worked exactly as he claimed.

There’s a section in the book where George Meade, watching a demonstration of liquid fire to defend a position, points out that the fire is effective at up to thirty feet and rifle fire is effective up to three thousand yards. This is an objection that most of the weapons described in the book run up against time and time again; they’re really useful only in close quarters fighting or would be extremely difficult to implement on the battlefield. Of all the weapons discussed in the book, which (if any) do you think at the time was most practical and could have actually influenced sieges and battles if followed up on? Which of the weapons you cover did you find to be the most interesting?

First, let me clarify Meade’s remark, because he was being loose with numbers to make a point. He was referring to squirting liquid fire from a garden engine—a device whose range might be, say, 60 or 70 feet—and the distance from which riflemen could shoot accurately was perhaps in the hundreds rather than thousands of yards. Nevertheless, he was correct that enemy soldiers could deliver lethal fire from well beyond the maximum range of the primitive flamethrower. Some of the proposed weapons may have killed or incapacitated a few nearby enemy combatants, which may have been useful in some situations, so we shouldn’t totally discount them. To answer your question, though, I doubt that any of the proposed weapons would have influenced a full-scale battle. Many were simply unsuitable for being weaponized or didn’t have the chemical or toxicologic properties that would make them effective on the battlefield. Which weapons interested me the most? Other than the binary cyanide shell already described, I’d say the artillery shell containing liquid chlorine. Its proponent had a good understanding of the properties of chlorine, but the technology necessary to implement the idea was decades away. Chlorine, of course, was used effectively in World War I and apparently very recently in the Middle East. In World War I, chlorine was released from cylinders rather than placed in artillery shells, but the rationale for its use was exactly that articulated during the Civil War.

One sentiment expressed by inventors and some military officials throughout the book is that advanced weapons of warfare are actually to be desired because the idea and use of such weapons results in short wars and long periods of peace; “Sharp wars are brief,” you quote the Lieber Code from 1863 as saying. Is there really any historical support for this idea? It seems that the more “scientific” and advanced technology in war has become, especially in the last century, the fighting has become more horrid and destructive, and not necessarily shorter.

Well, I’m not an expert in the tactics or strategy of war. It seems to me, though, that having advanced weapons is only one variable in how long wars last and that another is the willingness of decision makers to use them in light of political and other considerations. I think that, at least in today’s world, the “sharp wars are brief” dictum is too simplistic.

Chemical weapons have a bit of a lurid grip in our minds even today, it seems (or perhaps it’s just my mind). As you mention in Villainous Compounds, some governments (and terrorist organizations such as Aum Shinrikyo, responsible for the sarin attack on the Tokyo subway in 1995) use these weapons today, and I think the prospect of a chemical weapons attack causes anxiety in the minds of a lot of Americans. As a final question, has your research given you any thoughts about how chemical weapons are perceived and used today?

Our anxiety about chemical weapons is understandable. Not only do we associate them with terrorists and other ruthless groups, we see photos of the chemicals’ lifeless victims, who are often civilians. Chemical weapons seem particularly frightening and insidious because we imagine ourselves defenseless against horrible and invisible poisons that are spreading far and wide while the attacker skulks in the distance. This apprehension was not present during the Civil War, largely because highly effective agents—in terms of toxicity and suitability for weaponization—didn’t exist, military officials didn’t take chemical weapons seriously, people didn’t have real examples to frighten them, and civilians were not seen as likely targets for any kind of weapon. I wrote Villainous Compounds with hopes that readers could relate to its topic. Going back to a time when chemical weapons were being proposed but concerns about them were minimal can provide some insight about why we fear the weapons today.